Replace getList by a get_entries method
    
    The find_entries method is cumbersome to use: it requires keyword arguments
    for simple uses, and callers are tempted to ignore the 'truncated' flag
    it returns.
    Introduce a simpler method, get_entries, that returns the found
    list directly, and raises an errors if the list is truncated.
    Replace the getList method by get_entries.
    
    Part of the work for: https://fedorahosted.org/freeipa/ticket/2660